Loudspeakers, hereinafter referred to as electroacoustic transducers, are devices that convert electrical energy into energy acoustic oscillations. Electroacoustic transducers are utilized in many consumer products, such as household stereo systems, home theater systems, audio systems for automobiles, portable music devices, headphones, recording studio equipment, acoustic sensory equipment, and others. Demand for high quality sound production and/or recording from these and other products has generated great interest in the development of electroacoustic transducers that can convert electronic signals into sound waves with greater accuracy and higher definition.
One problem with known electroacoustic transducers is their reliance on moving components (e.g., voice coils and diaphragms) to produce acoustic oscillations in a two-step energy conversion process. In the first step, electric energy of a sound signal is converted into mechanical vibrations of a membrane attached to the electro acoustic transducer. In the second step, the mechanical vibrations of the membrane create acoustic oscillations in a surrounding gas medium (e.g., air). The membrane has a certain mass, an ultimate rigidity and given boundaries, which affect the quality of sound reproduced in the surrounding space during the second step. Thus, the quality of sound reproduction is physically limited by these aspects of the membrane. Some manufacturers have sought to overcome these challenges by producing different types of electroacoustic transducers that operate without the use of moving parts. For example, electroacoustic devices have been developed that create sound waves using areal electric discharge. However, known electroacoustic transducers employing areal electrical discharge may not perform optimally.
One example of an electroacoustic transducer that operates with ionized gas particles instead of a moving diaphragm is disclosed in U.S. Patent Application Publication No. 20090022340 A1 (the '340 publication) of Krichtafovich et al. The '340 publication discloses ion generation at one electrode, which is active due to the presence of discharge elements with a large surface curvature. Generated ions drift to the second electrode, which is passive due to the lack of discharge elements with a large surface curvature. In the drift process, a so-called ion wind is created, which is a macroscopic air flow. This flow also generates acoustic vibrations during modulation. However, the dipole radiation pattern, i.e., the generation of two opposing waves, requires the use of acoustic processing preventing an acoustic short circuit. This design may not allow for the achievement of high operational stability and may result in the occurrence of hissing, crackling, and arcing or spark discharge due to the asymmetry of the unipolar corona discharge process, particularly when the power output is increased. Ionization of surrounding gas molecules may serve as a conductor for ions of the same sign, which may prohibit self-stabilization of the process. As a result, the electrical discharge distributed in space in the form of moving ions may be allowed to “collapse” and change to a spark or arc discharge, resulting in audible hissing or crackling sounds.
Another example of an electroacoustic transducer that operates with ionized gas particles instead of a moving diaphragm is disclosed in U.S. Pat. No. 4,460,809 (the '809 patent) to Bondar. The '809 patent describes an electroacoustic transducer comprising rows of electrodes separated by sheets of dielectric material. Each adjacent row or electrodes is connected to an opposite pole of a voltage source. This design achieves a so-called bipolar corona discharge, whereby the corona discharge process involves two types of charged particles, i.e., cations and anions. However, during the ion drift process, the ions are allowed travel freely along a bended path around dielectric sheets from one electrode to another. As a result of the uninhibited movement of ions between adjacent electrodes, the system of the '809 patent may not provide conditions for a self-stabilization process to be realized. That is, the system of the '809 patent may allow an electrical discharge of moving ions distributed in space to “collapse” and change to a spark or arc discharge.
Another example of an electroacoustic transducer is disclosed in Ukrainian Patent No. 105,621 C2 to Chizhov et al. (“the '621 patent”). The electroacoustic transducer of the '621 patent includes a cathode and an anode having discharge elements that are arranged in a row and linearly spaced apart by not more than 4 mm. The discharge elements extend into a space between the cathode and anode (i.e., an “interelectrode space”) and are three-dimensional bodies with a large surface curvature. An electrical circuit connecting the anode and cathode to a voltage source includes current-limiting elements. The configuration of the electroacoustic transducer of the '621 patent may increase the uniformity of the electric field in the interelectrode space, thereby stabilizing the corona discharge and preventing the generated cations and anions from collapsing their spatial electric discharge into a spark or arc.
While the electroacoustic transducer of the '621 patent may be effective, further improvements to the generation and control of ionized gas particles in the operation of electroacoustic transducers may yet be realized to achieve improved sound quality at higher power levels.
The disclosed electroacoustic transducer is directed to overcoming one or more of the problems set forth above and/or other problems of the prior art.